Alumni Profile • Paul Larsen '89Witness to a root secret: A discovery for the hungry

In 1985, freshman Paul Larsen ’89 was struggling, pulling a low C in Chemistry 101A. Chemistry professor Larry Louters stepped in to help. “Without him I would have dropped out,” Larsen said.

In the summer of 2008, Larsen, now a biochemist at the University of California-Riverside, made a discovery that could dramatically improve crop production in some of the world’s hungriest countries.

Almost half of the world’s arable soil is clay-based, meaning it contains high levels of aluminum silicates. When the aluminum leaches out and combines with acids—naturally occurring acids or pollutants—it becomes toxic to most plants, severely limiting their growth.

Larsen discovered exactly how aluminum interrupts plant growth. Contrary to what most scientists thought, he found that aluminum itself in plant tissue doesn’t directly halt growth. By introducing random mutations in the model plant Arabidopsis—the plant kingdom equivalent of fruit flies or mice—Larsen found a factor in the plant’s genome called AtATR that functions as a built-in DNA surveillance system. When aluminum causes DNA damage in the growing root tip, AtATR alerts the plant of that damage and shuts down cell division and thus root growth. But if the AtATR surveillance system is broken or bypassed, Larsen explained, “plants aren’t able to sense the effects of aluminum, and they continue to grow even in an aluminum-toxic environment.”

That doesn’t sound like a healthy response, but Larsen hasn’t observed any diminishment in plants whose AtATR factor he’s broken, even dozens of generations later. Besides, if his genetic modification could be translated to food crops, first-generation seeds for each planting would ensure robust plants.

Because Arabidopsis is very similar to most flowering plants, Larsen is confident that corn and other food staples could be engineered to grow in the aluminum-toxic soils of much of South America, Africa and Indonesia. At the same time, he’s keenly aware of the many worrisome consequences that his discovery—like any genetic modification—could also cause.

“I see this as a way to make land more productive and to feed hungry people,” Larsen said. “Somebody else could say, ‘OK, now I’m going to tear down even more of the rain forest because you’ve given me the key to turn more of it into a farm.’ Every advance in knowledge has a positive and a negative dimension to it. As Christians, we must not only develop new knowledge, but also give guidance for its proper use.”

And that—passing on scientific knowledge in an ethical framework—is more important to Larsen than his breakthrough discovery. “Passing on to the next generation our present knowledge and the tools to discover their own knowledge, that’s what I go home proud about.”

In the course of all the basic biochemistry Larsen passes on to hundreds of public university students every year, he also communicates a conviction made abundantly clear to him in his recent discovery and the years of research that preceded it: “I tell them that given all the intricacies of creation—and we know only a fraction of them—I find it difficult to imagine this could all come together by chance.”

Privately he can be more direct: “Daily the Lord has guided my science. He was gracious enough to reveal to me a secret in His creation that nobody in history has ever seen. That’s quite an honor.”